SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5ac39d1bea53c5e346e71af69121d9887411f0aa8334814ad40a8c7ca37c4d74' 
  AND token = 'hPV8v2f3amHfnXul9TzcwAZo2EK1H2IDqUo8jPP9rpM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}